I thought you might be interested in some experiments I made with
COG LCDs. Note that all these applications are written using Texas
Instruments' MSP430. However, since I don't use an exotic assembler
but plain C, it should be easily portable to any other device, even without
SPI capability as shown by the first example.

Yes, indeed. I design portable devices, so the power is a key point.
One interesting thing: the 101x64 model has exactly the same pinout
as the Nokia 3310 (1 = VCC, 2 = CLK ... 6 = GND, 7 = VOUT, 8 = RESET).
But it's not the same controller. Nokia uses apparently a Philips controller
and this one uses a Samsung S6B0725A.